The Nigerian Red Cross says a blast that killed seven people in an auto parts market in a central Nigeria city was a bomb.
An internal Red Cross report viewed Thursday by The Associated Press says that two men on a motorbike had stopped in front of a shop in the city of Kaduna just before the explosion went off.
Kaduna state police spokesman Aminu Lawan said he was not aware of the Nigerian Red Cross report, but that the police's anti-bomb squad had concluded that the blast was accidental.
Lawan said the squad found acid batteries, a gas cylinder and other "active" materials stored in the small shop where the fire started.
Kaduna, which sits on Nigeria's dividing line between its largely Christian south and Muslim north, was at the heart of postelection violence in April.